Blackberry maker RIM to face third writedown on unsold smartphones due to strong competition from Apple and Android phones. Photograph: Jim Young/Reuters

BlackBerry-maker RIM faces having to make a third huge writedown on unsold stocks of smartphones and PlayBook tablets when its financial quarter ends on Saturday, analysts say. It would be the third large writeoff in three quarters.

Analysts also expect to see falling revenues and profits as the group struggles against Apple's iPhone at the high end and Android devices in the rest of the market, as well as a resurgent Nokia, which has begun to attack the western smartphone market in earnest.

RIM said on Tuesday night it had engaged JP Morgan Securities and RBC Capital Markets to help with a review of the business, confirming reports earlier in the week that there would be "significant" job cuts.

Canada's Globe and Mail had reported at least 2,000 posts would go while Reuters cited a source saying cuts could hit up to 6,000. The company said financial performance would "continue to be challenging" for the next few quarters.

RIM took a $485m (£310m) writedown against unsold stock of the PlayBook for its third fiscal quarter, ending in November 2011. For the fourth quarter, ending in February 2012, it wrote off $267m on unsold BlackBerry 7 handsets which it had launched the previous summer.

Wall Street consensus forecasts are for the company to have shipped 10.5m handsets, down 20% from 13.2m a year ago – at the same time as the smartphone market has grown by 50%. Revenues are forecast at $3.7bn, a 24% fall compared with a year ago. That would be in line with the 24% fall in the previous quarter, but smaller than at any time since summer 2009.

Mark Sue of RBC Capital Markets was even gloomier, suggesting that the company will only have shipped 9m handsets – a 30% fall year-on-year as its share erodes in the US – with revenues of $3.2bn, lower than at any time.

RIM's chief executive officer Thorsten Heins said: "These advisers [JP Morgan Securities and RBC Capital Markets] have been tasked to help us with the strategic review we referenced on our year-end financial results conference call and to evaluate the relative merits and feasibility of various financial strategies.

"RIM is going through a significant transformation as we move towards the BlackBerry 10 launch, and our financial performance will continue to be challenging for the next few quarters."

Neeraj Monga, an analyst at Veritas Investment Research in Toronto, said the writedowns were inevitable in the face of consumer and business indifference, notably to the PlayBook tablet.

"Clearly this stuff isn't selling," he told Bloomberg. "Despite all the writedowns they're taking on the inventory, these inventory levels are not dropping."

Monga maintains a buy recommendation on RIM's stock – currently at an eight-year low – in anticipation of the company being sold.

RBC's Sue said the promise later in the year of the new BB10 software was not obviously a "silver bullet" for the business to return to growth, and that it might even have to withdraw from some markets as cheap Android phones undercut margins.

Colin Gillis, an analyst at BGC Partners LP in New York, told Bloomberg that it was hard for customers to show interest in older phones when there was the promise – but only that – of the new one: "Until you have a new product, there's nothing to transition to," said Gillis, who advises selling RIM's stock. "It's still very much in the early stages."

Though RIM did not specify whether its previous writedowns have been to zero value or to expected sale value, at the start of the current quarter in March 2012 it still had $1bn in inventory, which is stock in its own warehouses and not shipped to suppliers. That compared with just $618m at the same period a year ago, in February 2011.

• RIM is losing another senior executive. Its chief legal officer is retiring after 12 years, joining an exit roster that includes the global head of sales Patrick Spence earlier this week, and the former co-CEOs and co-chairmen Mike Lazaridis and Jim Balsillie who departed in February.